I've never read this book, but it's main message is that almost any physial condition can be mimiced by dehydration. Reading reviews on Amazon might give you more insight into dehydration.

I myself was chronically thirsty and dehydrated (no matter how much water I drank) for many years until I discovered electrolysis water. Electrolysis breaks down water clusters from approx. 15-18 molecules per cluster to about 5-6. After several weeks of drinking this water, I finally felt rehydrated.

I think I remember reading (Teitelbaum perhaps) that chronic thirst can be indicative of hormonal imbalances.